Motor-driven power tools and similar devices have conventionally been connected to a commercial AC power source, a DC constant-voltage power source, and the like, but a growing number of power tools are now equipped with a secondary battery. Power tools employing a secondary battery are also referred to as cordless power tools. As these power tools continue to expand in type and application, the demand for greater battery capacity increases. While the battery pack for powering these power tools has traditionally been mounted directly on the body of the tool, a waist-belt-type power supply has also been proposed in the patent literature listed below. This power supply accommodates rechargeable batteries in a waist belt that can be worn about the user's waist.